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umn/source/change_history.rst

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+:original_name: en-us_topic_0054617978.html
+
+.. _en-us_topic_0054617978:
+
+Change History
+==============
+
+.. table:: **Table 1** Change History
+
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+   | Released On                       | What's New                                                                                                                                                                                                                                                                                             |
+   +===================================+========================================================================================================================================================================================================================================================================================================+
+   | 2020-07-17                        | Modified the following content:                                                                                                                                                                                                                                                                        |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | -  Added a note in section :ref:`Accessing a DCS Redis Instance <en-us_topic_0054235811>` to advise against hard-coding plaintext passwords in the code.                                                                                                                                               |
+   |                                   | -  Added an explanation of the **SYS.DCS** namespace and optimized the table layout in section :ref:`DCS Metrics <dcs-ug-0326019>`.                                                                                                                                                                    |
+   |                                   | -  Updated the picture that demonstrates viewing instance metrics in section :ref:`Setting Alarm Rules for Critical Metrics <dcs-ug-190905001>`.                                                                                                                                                       |
+   |                                   | -  Optimized the description about CIDR blocks for cross-VPC access and added the table caption in FAQ :ref:`Do DCS Instances Support Cross-VPC Access? <en-us_topic_0103202022>`                                                                                                                      |
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+   | 2020-05-30                        | Modified the following content:                                                                                                                                                                                                                                                                        |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | -  Changed the cluster instance type to Proxy Cluster in section :ref:`DCS <en-us_topic_0054235826>`.                                                                                                                                                                                                  |
+   |                                   | -  Removed description about creating multiple instances in batches and modified password complexity requirements in section :ref:`Creating a DCS Instance <en-us_topic_0054235810>`.                                                                                                                  |
+   |                                   | -  Removed the instance topology parameter in section :ref:`Viewing Details of a DCS Instance <en-us_topic_0054235812>`.                                                                                                                                                                               |
+   |                                   | -  Changed the default value of the **reserved-memory-percent** parameter to **0** and added a note clarifying that the configuration parameters supported by single-node and master/standby instances are different in section :ref:`Configuring Redis-Specific Parameters <en-us_topic_0054235814>`. |
+   |                                   | -  Modified the special characters that the passwords cannot contain in section :ref:`Changing Instance Passwords <en-us_topic_0054235820>`.                                                                                                                                                           |
+   |                                   | -  Removed the section which describes the function of viewing data storage statics of a Proxy Cluster instance.                                                                                                                                                                                       |
+   |                                   | -  Added a note clarifying that the backup policy function is not supported by single-node instances in section :ref:`Configuring a Backup Policy <en-us_topic_0062866097>`.                                                                                                                           |
+   |                                   | -  Removed Redis Server and Proxy metrics from section :ref:`DCS Metrics <dcs-ug-0326019>`.                                                                                                                                                                                                            |
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+   | 2020-03-25                        | Modified the following content:                                                                                                                                                                                                                                                                        |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | -  Changed the cluster instance type to Proxy Cluster in section :ref:`DCS <en-us_topic_0054235826>`.                                                                                                                                                                                                  |
+   |                                   | -  Modified the lists of supported and disabled Redis commands in section :ref:`Redis Command Compatibility <dcs-ug-180522002>`.                                                                                                                                                                       |
+   |                                   | -  Added the assured/maximum bandwidth parameter in section :ref:`DCS Instance Specifications <en-us_topic_0054235835>`.                                                                                                                                                                               |
+   |                                   | -  Moved the metrics originally described in section :ref:`Related Services <en-us_topic_0054235808>` to section :ref:`DCS Metrics <dcs-ug-0326019>` and updated the metrics supported by Cloud Eye.                                                                                                   |
+   |                                   | -  Modified instance creation parameters in :ref:`Creating a DCS Instance <en-us_topic_0054235810>` according to DCS console upgrade and parameter modifications.                                                                                                                                      |
+   |                                   | -  Modified instance details parameters in section :ref:`Viewing Details of a DCS Instance <en-us_topic_0054235812>` according to DCS console upgrade and parameter modifications.                                                                                                                     |
+   |                                   | -  Modified instance configuration parameters in section :ref:`Configuring Redis-Specific Parameters <en-us_topic_0054235814>`.                                                                                                                                                                        |
+   |                                   | -  Removed the function of stopping instances.                                                                                                                                                                                                                                                         |
+   |                                   | -  Added description about restrictions of starting instances in section :ref:`Starting DCS Instances <en-us_topic_0054235817>`.                                                                                                                                                                       |
+   |                                   | -  Changed parameter **Time Window** to **Maintenance** in section :ref:`Modifying an Instance's Maintenance Time Window <en-us_topic_0090713825>`.                                                                                                                                                    |
+   |                                   | -  Modified description about configuring instance backup policies in section :ref:`Configuring a Backup Policy <en-us_topic_0062866097>`.                                                                                                                                                             |
+   |                                   | -  Added chapter :ref:`Monitoring <dcs-en-ug-180424001>`, updated metrics supported by Cloud Eye, and added description about operations of viewing monitoring data and setting alarm rules.                                                                                                           |
+   |                                   | -  Changed the supported number of DBs for single-node and master/standby instances in section :ref:`Does DCS Support Data Read/Write in Multiple Databases? <en-us_topic_0071964265>`                                                                                                                 |
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+   | 2019-04-12                        | Accepted in OTC-4.0/Agile-04.2019.                                                                                                                                                                                                                                                                     |
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+   | 2019-03-30                        | Modified the following content:                                                                                                                                                                                                                                                                        |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | -  Removed support for creating DCS instances with the specification of 1 GB in sections :ref:`Advantages <en-us_topic_0054235833>`, :ref:`DCS Instance Specifications <en-us_topic_0054235835>`, and :ref:`Creating a DCS Instance <en-us_topic_0054235810>`.                                         |
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+   | 2018-09-05                        | Modified the following content:                                                                                                                                                                                                                                                                        |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | -  Opened certain Redis cluster commands. For details about compatibility with DCS commands, see :ref:`Redis Command Compatibility <dcs-ug-180522002>`.                                                                                                                                                |
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+   | 2018-03-16                        | Added the following content:                                                                                                                                                                                                                                                                           |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | -  Added the procedure for using a Redis Java (Jedis) client to access a DCS instance. For details, see :ref:`Accessing a DCS Redis Instance <en-us_topic_0054235811>`.                                                                                                                                |
+   |                                   | -  Added descriptions about the Redis-specific parameter **notify-keyspace-events**, anddeleted descriptions about the Redis-specific parameter **maxclients**. For details, see :ref:`Configuring Redis-Specific Parameters <en-us_topic_0054235814>`.                                                |
+   |                                   | -  Added the procedures for modifying the time window and security group of a DCS instance. For details, see :ref:`Modifying an Instance's Maintenance Time Window <en-us_topic_0090713825>` and :ref:`Modifying an Instance's Security Group <en-us_topic_0090713826>`.                               |
+   |                                   | -  Added :ref:`Do DCS Instances Support Cross-VPC Access? <en-us_topic_0103202022>` in chapter :ref:`FAQs <en-us_topic_0054235821>`.                                                                                                                                                                   |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | Modified the following content:                                                                                                                                                                                                                                                                        |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | -  Changed instance password complexity rules.                                                                                                                                                                                                                                                         |
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+   | 2017-11-08                        | Added the following content:                                                                                                                                                                                                                                                                           |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | -  Provided support for DCS instances in cluster mode.                                                                                                                                                                                                                                                 |
+   |                                   | -  Added sections :ref:`Modifying DCS Instance Specifications <en-us_topic_0063519673>` and :ref:`Backing Up and Restoring DCS Instances <en-us_topic_0062866096>`.                                                                                                                                    |
+   |                                   | -  Added the **Time Window** parameter.                                                                                                                                                                                                                                                                |
+   |                                   | -  Added section :ref:`Setting Up Environments <en-us_topic_0077665192>`.                                                                                                                                                                                                                              |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | -  Added some FAQs in chapter :ref:`FAQs <en-us_topic_0054235821>`.                                                                                                                                                                                                                                    |
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+   | 2017-05-30                        | This issue is the third official release, which incorporates the following changes:                                                                                                                                                                                                                    |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | -  Added descriptions about batch deletion of DCS instances.                                                                                                                                                                                                                                           |
+   |                                   | -  Added descriptions about the Redis-specific parameter **latency-monitor-threshold**.                                                                                                                                                                                                                |
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+   | 2017-04-28                        | Added the following content:                                                                                                                                                                                                                                                                           |
+   |                                   |                                                                                                                                                                                                                                                                                                        |
+   |                                   | -  Added descriptions of DCS metrics monitored by Cloud Eye.                                                                                                                                                                                                                                           |
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+   | 2017-04-05                        | This issue is the first official release.                                                                                                                                                                                                                                                              |
+   +-----------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

umn/source/faqs/can_dcs_be_accessed_over_public_networks.rst

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+:original_name: en-us_topic_0054235827.html
+
+.. _en-us_topic_0054235827:
+
+Can DCS Be Accessed over Public Networks?
+=========================================
+
+DCS cannot be accessed over public networks. The ECS serving as your Redis client and the DCS instances that the Redis client want to access must belong to the same VPC.

umn/source/faqs/can_i_modify_configuration_parameters_of_dcs_instances.rst

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+:original_name: en-us_topic_0054235828.html
+
+.. _en-us_topic_0054235828:
+
+Can I Modify Configuration Parameters of DCS Instances?
+=======================================================
+
+You can modify configuration parameters for DCS instances in the **Running** state. Note that configuration parameters of DCS instances in Proxy Cluster mode are not modifiable.

umn/source/faqs/can_i_recover_data_from_deleted_dcs_instances.rst

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+:original_name: en-us_topic_0054235829.html
+
+.. _en-us_topic_0054235829:
+
+Can I Recover Data from Deleted DCS Instances?
+==============================================
+
+Data that is automatically deleted by DCS instances or manually deleted by users using Redis clients cannot be recovered. By default, data is not evicted from DCS instances. However, you can modify the value of the maxmemory-policy parameter to adjust the eviction policy, and then DCS instances evict keys according to the eviction policy.
+
+If a DCS instance is deleted, instance data will also be removed and cannot be recovered. Therefore, exercise caution when deleting DCS instances.
+
+Master/Standby DCS instances support data backup. If you have backed up the instance data before deleting them, the deleted instance data can be recovered.

umn/source/faqs/do_dcs_instances_in_cluster_mode_support_native_redis_clusters.rst

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+:original_name: en-us_topic_0072544389.html
+
+.. _en-us_topic_0072544389:
+
+Do DCS Instances in Cluster Mode Support Native Redis Clusters?
+===============================================================
+
+DCS instances in cluster mode do not support native Redis clusters. DCS clusters use the proxy-based cluster mode, so when you query the parameters of the native Redis cluster, DCS retains the default values for some parameters, for example, **cluster_enabled:0**.

umn/source/faqs/do_dcs_instances_support_cross-vpc_access.rst

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+:original_name: en-us_topic_0103202022.html
+
+.. _en-us_topic_0103202022:
+
+Do DCS Instances Support Cross-VPC Access?
+==========================================
+
+Generally, VPCs are isolated from each other and ECSs cannot access DCS instances that belong to a different VPC from these ECSs.
+
+However, by establishing VPC peering connections between VPCs, ECSs can access DCS instances across VPCs.
+
+When using VPC peering connections to access DCS instances across VPCs, adhere to the following rules:
+
+.. table:: **Table 1** Client CIDR block constraints
+
+   +-----------------------------------+-------------------------------------+
+   | CIDR Blocks of DCS Instances      | CIDR Blocks Not Allowed for Clients |
+   +===================================+=====================================+
+   | 172.16.0.0/12 to 172.16.0.0/24    | 192.168.1.0/24                      |
+   |                                   |                                     |
+   |                                   | 192.168.2.0/24                      |
+   |                                   |                                     |
+   |                                   | 192.168.3.0/24                      |
+   +-----------------------------------+-------------------------------------+
+   | 192.168.0.0/16 to 192.168.0.0/24  | 172.31.1.0/24                       |
+   |                                   |                                     |
+   | 10.0.0.0/8 to 10.0.0.0/24         | 172.31.2.0/24                       |
+   |                                   |                                     |
+   |                                   | 172.31.3.0/24                       |
+   +-----------------------------------+-------------------------------------+
+
+.. note::
+
+   -  The right column lists the CIDR blocks used by the subnets of the resource tenant. The clients cannot use these subnets.
+   -  For more information about creating and using VPC peering connections, see the *Virtual Private Cloud User Guide*.

umn/source/faqs/do_i_need_to_enter_a_password_when_accessing_a_dcs_instance_where_can_i_obtain_the_password.rst

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+:original_name: en-us_topic_0066854411.html
+
+.. _en-us_topic_0066854411:
+
+Do I Need to Enter a Password When Accessing a DCS Instance? Where Can I Obtain the Password?
+=============================================================================================
+
+Redis allows clients to access cache service directly without any password.
+
+In DCS, additional efforts have been made to harden Redis. A client must enter the correct password before it is allowed to access DCS instances. The instance password is manually assigned when you are creating a DCS instance.

umn/source/faqs/does_dcs_support_common_redis_clients_such_as_jedis.rst

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+:original_name: en-us_topic_0054235822.html
+
+.. _en-us_topic_0054235822:
+
+Does DCS Support Common Redis Clients Such as Jedis?
+====================================================
+
+DCS supports all clients compatible with Redis, including Jedis. You can download Redis clients from http://redis.io/clients.

umn/source/faqs/does_dcs_support_data_persistence.rst

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+:original_name: en-us_topic_0054235825.html
+
+.. _en-us_topic_0054235825:
+
+Does DCS Support Data Persistence?
+==================================
+
+Only master/standby and Proxy Cluster DCS instances support data persistence.

umn/source/faqs/does_dcs_support_data_read_write_in_multiple_databases.rst

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+:original_name: en-us_topic_0071964265.html
+
+.. _en-us_topic_0071964265:
+
+Does DCS Support Data Read/Write in Multiple Databases?
+=======================================================
+
+Both single-node and master/standby DCS instances support data read/write in multiple databases. By default, single-node and master/standby DCS instances can read and write data in 256 databases (databases 0-255).
+
+DCS instances in Proxy Cluster mode do not support data read/write in multiple databases.

umn/source/faqs/does_standby_cache_node_remain_synchronized_with_master_cache_node.rst

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+:original_name: en-us_topic_0054235824.html
+
+.. _en-us_topic_0054235824:
+
+Does Standby Cache Node Remain Synchronized with Master Cache Node?
+===================================================================
+
+Generally, updates to the master cache node are automatically and asynchronously replicated to the standby cache node. This means that data in the standby cache node may not always be consistent with data in the master cache node. This inconsistency is typically seen in either of the following situations:
+
+-  The input/output (I/O) write speed of the master cache node is faster than the synchronization speed of the standby cache node.
+-  There is network latency between the master and standby cache nodes.
+
+If a failover occurs when some data is not yet replicated to the standby cache node, the unreplicated data may be lost after the failover.

umn/source/faqs/how_to_select_and_configure_a_security_group.rst

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+:original_name: en-us_topic_0082605221.html
+
+.. _en-us_topic_0082605221:
+
+How to Select and Configure a Security Group?
+=============================================
+
+An ECS can communicate with a DCS instance if they belong to the same VPC and security group rules are configured correctly.
+
+It is recommended that the ECS and DCS instance belong to the same security group. After a security group is created, the security group rules, by default, include a rule allowing members in the security group to access each other without any restrictions.
+
+If the ECS and DCS instance belong to different security groups, add security group rules to ensure that the ECS and DCS instance can access each other.
+
+.. note::
+
+   The example rules provided here are based on the assumption that:
+
+   -  The ECS on which the client runs belongs to security group **sg-ECS**, and the DCS instance that the client will access belongs to security group **sg-DCS**.
+   -  The port number of the DCS instance is 6379.
+   -  The remote end is a security group or an IP address.
+
+
+.. figure:: /_static/images/en-us_image_0000001340638257.png
+   :alt: **Figure 1** Security group rules allowing the ECS to access the DCS instance
+
+   **Figure 1** Security group rules allowing the ECS to access the DCS instance
+
+
+.. figure:: /_static/images/en-us_image_0000001288319004.png
+   :alt: **Figure 2** Security group rules making the DCS instance accessible to the ECS
+
+   **Figure 2** Security group rules making the DCS instance accessible to the ECS

umn/source/faqs/index.rst

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+:original_name: en-us_topic_0054235821.html
+
+.. _en-us_topic_0054235821:
+
+FAQs
+====
+
+-  :ref:`Does DCS Support Common Redis Clients Such as Jedis? <en-us_topic_0054235822>`
+-  :ref:`Should I Install Redis If I Already Have a DCS Instance? <en-us_topic_0054235823>`
+-  :ref:`Do I Need to Enter a Password When Accessing a DCS Instance? Where Can I Obtain the Password? <en-us_topic_0066854411>`
+-  :ref:`Does Standby Cache Node Remain Synchronized with Master Cache Node? <en-us_topic_0054235824>`
+-  :ref:`Does DCS Support Data Persistence? <en-us_topic_0054235825>`
+-  :ref:`Can DCS Be Accessed over Public Networks? <en-us_topic_0054235827>`
+-  :ref:`Can I Modify Configuration Parameters of DCS Instances? <en-us_topic_0054235828>`
+-  :ref:`Can I Recover Data from Deleted DCS Instances? <en-us_topic_0054235829>`
+-  :ref:`What Is the Default Data Eviction Policy? <en-us_topic_0054235830>`
+-  :ref:`What Should I Do If the Connection Between My Redis Client and the DCS Instance Times Out? <en-us_topic_0054235831>`
+-  :ref:`Why Is Available Memory of Unused DCS Instances Less Than Total Memory? Why Is Memory Usage of Unused DCS Instances Greater Than Zero? <en-us_topic_0057984494>`
+-  :ref:`Does DCS Support Data Read/Write in Multiple Databases? <en-us_topic_0071964265>`
+-  :ref:`Why Can't I Back Up or Scale Up My DCS Instances? <en-us_topic_0072544388>`
+-  :ref:`Do DCS Instances in Cluster Mode Support Native Redis Clusters? <en-us_topic_0072544389>`
+-  :ref:`Why Do My DCS Instances Sometimes Become Unavailable While They Are in Running State? <en-us_topic_0077673452>`
+-  :ref:`Why Is the Used Instance Memory Displayed on Cloud Eye Console Slightly Higher than the Instance Available Memory? <en-us_topic_0078401074>`
+-  :ref:`How to Select and Configure a Security Group? <en-us_topic_0082605221>`
+-  :ref:`Do DCS Instances Support Cross-VPC Access? <en-us_topic_0103202022>`
+
+.. toctree::
+   :maxdepth: 1
+   :hidden: 
+
+   does_dcs_support_common_redis_clients_such_as_jedis
+   should_i_install_redis_if_i_already_have_a_dcs_instance
+   do_i_need_to_enter_a_password_when_accessing_a_dcs_instance_where_can_i_obtain_the_password
+   does_standby_cache_node_remain_synchronized_with_master_cache_node
+   does_dcs_support_data_persistence
+   can_dcs_be_accessed_over_public_networks
+   can_i_modify_configuration_parameters_of_dcs_instances
+   can_i_recover_data_from_deleted_dcs_instances
+   what_is_the_default_data_eviction_policy
+   what_should_i_do_if_the_connection_between_my_redis_client_and_the_dcs_instance_times_out
+   why_is_available_memory_of_unused_dcs_instances_less_than_total_memory_why_is_memory_usage_of_unused_dcs_instances_greater_than_zero
+   does_dcs_support_data_read_write_in_multiple_databases
+   why_cant_i_back_up_or_scale_up_my_dcs_instances
+   do_dcs_instances_in_cluster_mode_support_native_redis_clusters
+   why_do_my_dcs_instances_sometimes_become_unavailable_while_they_are_in_running_state
+   why_is_the_used_instance_memory_displayed_on_cloud_eye_console_slightly_higher_than_the_instance_available_memory
+   how_to_select_and_configure_a_security_group
+   do_dcs_instances_support_cross-vpc_access

umn/source/faqs/should_i_install_redis_if_i_already_have_a_dcs_instance.rst

@@ -0,0 +1,8 @@
+:original_name: en-us_topic_0054235823.html
+
+.. _en-us_topic_0054235823:
+
+Should I Install Redis If I Already Have a DCS Instance?
+========================================================
+
+It is not necessary to install Redis in this case. You can access your DCS instance through a Redis client.

umn/source/faqs/what_is_the_default_data_eviction_policy.rst

@@ -0,0 +1,40 @@
+:original_name: en-us_topic_0054235830.html
+
+.. _en-us_topic_0054235830:
+
+What Is the Default Data Eviction Policy?
+=========================================
+
+Data is evicted from the cache based on the user-defined space limit in order to make space for new data.
+
+By default, data is not evicted from DCS instances. In the current version of DCS, you can select an eviction policy.
+
+When maxmemory is reached, you can select one of the following six eviction policies:
+
+-  noeviction
+
+   When the memory limit is reached, DCS instances return errors to clients and no longer process write requests or other requests that could result in more memory being used. However, DEL and a few more exception requests can continue to be processed.
+
+-  allkeys-lru
+
+   DCS instances try to evict the least recently used keys first, in order to make space for new data.
+
+-  volatile-lru
+
+   DCS instances try to evict the least recently used keys with an expire set first, in order to make space for new data.
+
+-  allkeys-random
+
+   DCS instances evict random keys in order to make space for new data.
+
+-  volatile-random
+
+   DCS instances evict random keys with an expire set, in order to make space for new data.
+
+-  volatile-ttl
+
+   DCS instances evict keys with an expire set, and try to evict keys with a shorter time to live (TTL) first, in order to make space for new data.
+
+.. note::
+
+   If the configured policy is volatile-lru, volatile-random, or volatile-ttl, and no keys match the configured policy, the eviction behavior will match noeviction.

umn/source/faqs/what_should_i_do_if_the_connection_between_my_redis_client_and_the_dcs_instance_times_out.rst

@@ -0,0 +1,12 @@
+:original_name: en-us_topic_0054235831.html
+
+.. _en-us_topic_0054235831:
+
+What Should I Do If the Connection Between My Redis Client and the DCS Instance Times Out?
+==========================================================================================
+
+Reconnect your client to the DCS instance.
+
+The timeout is probably due to network connectivity problems or DCS instance errors. For example, if your DCS instance is overloaded or experiences a failover, your Redis client returns the error message "Connection timed out" or "Connection reset by peer".
+
+Some Redis clients do not support automatic reconnection. If you use these Redis clients, the applications that use DCS must be able to proactively initiate reconnection.

umn/source/faqs/why_cant_i_back_up_or_scale_up_my_dcs_instances.rst

@@ -0,0 +1,9 @@
+:original_name: en-us_topic_0072544388.html
+
+.. _en-us_topic_0072544388:
+
+Why Can't I Back Up or Scale Up My DCS Instances?
+=================================================
+
+-  Only master/standby and Proxy Cluster DCS instances can be backed up and restored. Single-node DCS instances do not support backup or restoration.
+-  DCS instance backup and scale-up are new functions provided by DCS. If your DCS instances were created long time ago, the version of these DCS instances is not upgraded and therefore cannot support some new functions (such as DCS instance backup and scale-up). You can contact technical support personnel to upgrade your DCS instance version. After the upgrade, you can back up and scale up your DCS instances.